The WATERGATE scheme is the most accepted building block to suppress the strong water resonance in NMR experiments of samples dissolved in H₂O. It is basically a water-selective spin echo building block and it is easily incorporated in the most of 2D, 3D, and 4D homo- and heteronuclear NMR experiments.

Easy implementation on AVANCE spectrometers equipped with pulsed field gradients (PFGs).

For further details about implementation of WATERGATE scheme in AVANCE spectrometers see:

• Tutorial: The WATERGATE scheme.

See a list of available pulse programs containing the WATERGATE scheme with 3-9-19 and with the water selective 90 pulses.

The most standard way to implement the WATERGATE scheme in a pulse program is using the 3-9-19 approach:

... 50u UNBLKGRAD p16:gp1 d16 pl18:f1 p27*0.231 ph3 d19*2 p27*0.692 ph3 d19*2 p27*1.462 ph3 d19*2 p27*1.462 ph4 d19*2 p27*0.692 ph4 d19*2 p0*0.231 ph4 46u p16:gp2 d16 4u BLKGRAD ...

in which:

• pl18 is the power level for 3-9-19-pulse from the f1 channel
• p27is the 90 degree pulse at pl18. The same value is used for p0 which is used for fine adjustment.
• d19 is the delay for binomial water suppression. Sidebands must be carefully avoided from the distance (d) of next null (in Hz) (1/(2*d).
• p16 (1ms), d16 (100u), gpz1 (20), gpz2 (20), gpnam1 (SINE.100), and gpnam2 (SINE.100) are gradient parameters defining PFGs. Typical values in parenthesis.
• All phase programs must be specified at the end of the pulse program.

See More info about WATERGATE ..

Other WATERGATE related approaches:

• wg element: Use of 90 water selective pulse
• es element: Excitation sculpting using 180 water selective pulse
• w5 element: Excitation scultping using high-power DANTE-based suppression